Isophthalic acid derivatives



United States Patent Ofifice 3,312,695 Patented Apr. 4, 1967 The present application relates to novel compounds having valuable physiological properties and more particularly improved analgetic properties and correspond ing to the following general formula ii C-Rr R4 ill-R wherein the radicals R and R are the same or different lower alkoxy radicals or at least one of the radicals R and R means the group 5 N R. wherein each of the radicals R and R which can be the same or diflFerent radicals, means hydrogen, alkyl radicals, aryl radicals or aralkyl radicals, or form a heterocyclic ring together with the nitrogen atom, and only one of the two radicals R and R represents an unsubstituted alkenyl radical or an alkenyl radical substituted by at least one alkyl radical or by at least one phenyl radical, whereas the other of the two radicals R and R, means a hydroxyl group, an alkoxy radical, an alkenyloxy radical or an alkinyloxy radical. Allyl radicals, butylene-Z radicals and the like preferably come in question as alkenyl radical.

These novel compounds are obtained according to the invention by subjecting to a Claisen rearrangement a derivative of 4-hydroxy-isophthalic acid having the general formula o-rt,

ll s wherein the radicals R and R have the above meanings and one of the two radicals R and R is hydrogen whereas the other of the two radicals R and R means an unsubstituted alkenyloxy radical, preferably an allyloxy, butylene-Z-oxy radical, etc., or an alkenyloxy radical substituted by at least one alkyl radical or phenyl radical, preferably an allyloxy, butylene-Z-oxy radical, etc., whereupon one can, if desired, etherify the resulting product with a compound yielding an alkyl radical or dialkylaminoalkyl radical.

As starting materials the isophthalic acid dimethyl or diethyl or dibenzyl ester bearing in 4-position a substituted or unsubstituted allyloxy radical will be used for economic reasons. Other dialkyl or diaralkyl esters can naturally also be used with the same success, new valuable compounds being obtained by the said Claisen rearrangement.

Moreover, instead of the esters containing in 4-position a substituted or unsubstituted alkenyloxy radical, e.g. allyloxy radical, the corresponding esters substituted in 5-position may also be used as starting products, and the rearrangement from 5-position to 4-position effected.

Derivatives of isophthalic acid are further suitable as starting materials in which at least one carboxyl group is replaced by a radical of the folowing formula wherein R represents a heterocyclic base together with the nitrogen atom. The said heterocyclic radical can hereby, if desired, comprise further hetero atoms, e.g. a second nitrogen atom or an oxygen or sulphur atom, and if desired further substituents, preferably alkyl or alkoxy radicals. Examples of such radicals are the morpholine and piperidine radical, as well as derivatives thereof.

The Claisen rearrangement or transposition of the invention can be eifected according to conventional methods, preferably by direct heating to 180200 C. for example. It can also be performed in the presence of a suitable solvent, such as tetralin or dimethylaniline and the like.

Some examples of suitable starting materials are 4-allyloxy isophthalic acid dimethyl ester, 4-crotyloxy isophthalic acid dimethyl ester, 4-cinnamyloxy isophthalic acid dimethyl ester, 3-carboxy morpholido-4-allyloxy benzoic acid methyl ester, 3-carboxypiperidido-4-crotyloxy-l-benzoic acid methyl ester, and the like.

The present invention further relates to ethers of compounds of the above general Formula I which are obtained by etherifying compounds of the general Formula I in conventional manner.

This additional embodiment of the etherification can be effected by reacting compounds of the above Formula I in the presence of a solvent with a compound yielding an alkyl radical or a dialkylaminoalkyl radical.

The ether formation preferably takes place with an alkyl or alkylene halide in the presence of sodium methyl- One advantageously opate or of potassium carbonate. erates thereby in a suitable solvent, e.g., acetone.

The invention is described in greater detail with reference to the following examples, without however being restricted thereto.

EXAMPLE 1 g. of 4-allyloxy isophthalic acid dimethyl ester were heated for 10 hours at 180-200 C. in an oil bath in a 250 cm. content round-bottomed flask provided with a reflux cooler. The course of the transposition can be readily followed in a thin layer chromatogram. After 8-10 hours no more starting material can be detected. The resulting transposition product is hereupon distilled in high vacuo for purification and the oil which has solidified to a crystalline mass is recrystallized from petroleum ether. B.P. C., 1 mm. One obtains 81 g. (81% of the theory) of 5-allyl-4-hydroxy-isophthalic acid dimethyl ester having a melting point of 61-63 C.

EXAMPLE 2 50 g. of 4-crotyloxy isophthalic acid dimethyl ester are gradually heated to 200 C. in an oil bath in a 100 cm. content round-bottomed flask provided with a reflux cooler. After 8-10 hours no more starting material can be detected in a thin layer chromatogram. The heating is interrupted and the transposition product distilled in high vacuo for purification. B.P. 147 C., 0.8 mm. The distilled oil solidifies after a short time to a crystalline massand is recrystallized from petroleum ether. M.P. 40 C. One obtains 37 g. (74% of the theory) of 5- 3 (ec-methyl-allyl)-4-hydroxy-isophthalic acid dimethyl ester.

EXAMPLE 3 40 g. of 4-cinnamyloxy isophthalic acid dimethyl ester and refluxed until no more starting material can be de-v tected in a thin layer chromatogram. The diethyl aniline is carefully removed in vacuo and the residue discoloured with a small amount of animal charcoal. After are heated for 8-10 hours to 180-200 C. in an oil bath 5 clfystanizing from t ll one obtains (65% in a 100 cm. content round-bottomed flask. After this yleld) of 3'(.:arbO.Xyplpend1d 4 time, no more starting material can be detected in a thin acld methyl ester having of 56 layer chromatogram. The content of the flask is dissolved in 150 cm. of hot alcohol and discoloured with EXAMPLE 8 a small amount of animal charcoal. Crystallization oc- 10 10 gof 5-allyl-4-hydroxy-1sophthal1c -ac1d dimethyl curs after cooling. One obtains g. (62% of the ester (obtained according to the above Example 1 or Exgi i g h fi g fg ggg g' acld ample 4) are introduced into a solution of 0.9 g. of soime y es er avmg a dium in 50 cm. of methanol and the mixture is heated EXAMPLE 4 15 to 60 C. 6 g. of methyl iodide in 10 cm. of methanol 50 of 4 anyloxy isophthalic acid dimethyl ester are are allowed to drip in within minutes and the mixture dissolved in 50 3 of diethylanfline and refluxed for is subsequently refluxed until the solution reacts neutral. 840 hours After'this time no more siarting material The solvent is then carefully removed in vacuo, the residue can be dete'cted in a thin layer chromatooram The dissolved in ether, the mixture shaken out 3 times with b I ethylaniline is carefully removed in vacuo, the residue 2,N'SOd1um hydroxide herqupon washed fi dissolved in ether and washed with 2 N-hydrochloric acid i 2 Nihydrochlonc and and hen with Water and dned and water. The residue of the ether solution is distilled it sodlufn i a i T resldueBof the gum/mated in vacuo and recrystallized from petroleum ether. One at er Solutlon 1S dlsn led m vacuo' 7 obtains 40 g. (80% of the theory) of 5-allyl-4-hydroxy- 2 EXAMPLE 9 o J 1sophthal1c acid dimethyl ester having a M.P. of 62 C. 8 g of anhydrous potassium carbonate is added to a EXAMPLE 5 solution of 10 g. of 'S-(a-methyl-allyl)-4-hydroxy-iso- 50 of 4 crotyloxy isophthalic acid dimethyl ester are phthahc acid dimethyl ester (obtained according to data dissolved in 80 -cm. of tetralin and refluxed for 10 hours. i the aboave Examples 2 or 5 and 8 of allyl bromlde After this time no more starting material can be detected 30 m 50 of heated at temperature in a thin layer chromatogram. The tetralin is hereupon i 12 hours Whlle The PPtas1um carbonate carefully removed in vacuo and the residue is distilled in then filiered the resultmg Sh 1t10n conccntratFid high vacuo. After crystallization from petroleum ether dlssoived ether and Wlth sodlum hydroxlde one obtains (70% of the theory) of solution. The ether solut on is hereupon first washed allyl)-4-hydroxy-isophthalic acid dimethyl ester having a 35 Wlth 2 f d then with water, and of evaporated. The remaining 011 is distilled 1n vacuo. EXAMPLE 6 One obtains 7 g. (70% of the theory) of 5-(a-methylallyl)-4-allyloxy-isophthalic acid dimethyl ester having a 10 g. of 3-carboxymorpholido-4 allyloxy benzoic acid y f 55 0/01 mm. Aft crystallizing f a meflgyl ester are gradually heated m an 9 bath 9 4O methanol-Water mixture, one obtains needles having a 200 C. After 10 hours no more startlng material can p f 30420 C be fifttected m a F layer cPromatogram- The trans Further examples of compounds obtainable according pos1t1on product is dissolved 1n 50 cm. of alcohol and to [hg i tion and having the general formula discoloured with animal charcoal. Crystallization occurs 0 O 0 CH8 after concentration of the alcohol. One obtains 6.4 g. (64% of the theory) of 3-carboxymorpholido-4-hydroxy- S-allyl-benzoic acid methyl ester having a M.P. of 90- EXAMPLE 7 R4 000cm 15 g. of 3-carboxypiperidido-4-crotyloxy benzoic acid R3 methyl ester are dissolved in 70 cm. of diethyl aniline are cited in the following table.

TABLE Example R3 R4 Yield, M.p resp. percent B.p. in C.

10 OCH3 CHg-CH=CH1 s0 132l11mn 11 --OC2H5 -CHz-CH=CH2 158l1mm 12.- -OCHgCH -CH3 -OH -CH=CH2 135/0.5mm

TAB LE Analgesia DL N0.

ED50 in lug/kg. Mouse, mg./kg.

I 26. 5 650 II 32 250 The analgetic efficacy was determined according to the Hal-plate method of Chen and Beckrnann (Science, 113, 631, 1951).

What I claim is:

1. A compound of the formula ll I -31 a wherein each of R and R is a member selected from the group consisting of lower alkoxy, morpholino, and piperidino, and one of R and R; is a member selected from the group consisting of unsubstituted lower alkenyl and lower alkenyl substituted by a member selected from the group consisting of lower alkyl and phenyl, and the other R and R is a member selected from the group consisting of hydroxyl, lower alkoxy, lower alkenyloxy and lower alkinyloxy.

2. 5-ally l-4-hydroxy-isophthalic acid dimethyl ester.

3. 5 (a methyl-allyl)-4-hydroxy-isophtha1ic acid dimethyl ester.

4. 5 (oz phenyl-allyl)-4-hydroxy-isophthalic acid di methyl ester.

5. 3 morpholinocarbonyl 4 hydroxy-S-allyl-benzoic acid methyl ester.

6. 3 piperidinocarbonyl 4 hydroxy 5 (a methylal1yl)-benzoic acid methyl ester.

7. 5-allyl-4-methoxy-isophthalic acid dimethyl ester.

8. 5 (a methyl-allyl)-4-al1yloxy-is0phthalic acid dimethyl ester.

9. 5-allyl-4-ethoxy-isophthalic acid dimethyl ester.

10. 5-allyl-4-propoxy-isophthalic acid dimethyl ester.

11. S-allyl-4-allyloxy-isophthalic acid dimethyl ester.

12. S-allyl-4-butoxy-isophthalic acid dimethyl ester.

13. 5-allyl-4-benzyloxy-isophthalic acid dimethyl ester.

14. S-(a-methyl-aIlyl)-4-propynyloxy-isophthalic acid dimethyl ester.

15. 5-allyl-4-propynyloxy-isophthalic ester.

16. S-(a-phenyl-alIyI)-4--methoxy-isophthalic acid dimethyl ester.

acid dimethyl No references cited.

ALEX MAZEL, Primzuy Examiner.

I. TOVAR, Assistant Examiner. 

